An intelligent network is an architecture for generating and providing services, the most important feature of which is being capable of providing various special value-added services rapidly, conveniently, flexibly, and economically. An online charging system (OCS) achieves the separation between the service control and the charging, which is the development direction of charging in the future. Currently, there are already more and more operators using the OCS locally or entirely.
With the development of economy, the requirements of people of using international roaming calls are increasing. Since the international roaming calls relate to different countries, the international roaming communication fee will also increase gradually. Under this development trend, a technical solution for reducing the international roaming fee of the subscriber is proposed for the callback service. The so-called “callback” refers to: the subscriber in a high-charging country and area transfers a call request to the low-charging area so as to be charged according to the local relatively low fee rate, by using the market opportunity existing in the price difference of the international long distance call charging between various countries.
The conventional callback service generally contains two services: a pre-payment calling system (PPS) service and a Call Back service. The PPS service is mainly used to achieve the calling and charging of both parties, and the Call Back service is mainly used to initiate the calls to both parties and associate these two calls. The callback process generally is: the Call Back service firstly calls one party A and triggers a being-called procedure of the PSS service; after A replies, the Call Back service calls the other party B and also triggers the being-called procedure of the PPS service; after B replies, the Call Back service associates these two calls and completes the callback. However, after adopting the above callback solution, there may exist problems in three aspects as follows.
1. The conventional callback system has strong coupling and low efficiency. Generally, the Call Back service itself does not have charging function and thus needs to cooperate with other charging modules or systems (such as PPS service) to fulfill the charging of callback. As it needs the cooperation of two services to implement a callback system, the efficiency is low. Additionally, when the PPS service and the Call Back service belong to different providers respectively, correct callback charging can not be achieved, which is disadvantageous for service promotion.
2. It is unable to achieve flexible and correct charging. In the above callback solution, the being-called procedure of the PPS needs to be triggered twice; wherein in terms of the timing, the call duration of A and B is equal to the call duration of B, but the timing for A is equal to the sum of the duration of A waiting for the reply of B after the reply of A and the call duration of B, and thus the A will be overcharged by the fee which is charged for the duration of A waiting for the reply of B, which will cause the payment of A more than the charging of the real call of A.
3. There is a problem regarding the achievement of the number display of callback. In the above solution, in order to distinguish the calling and called parties of the callback, the being-called procedure of the PPS needs to add a prefix before the calling number of the callback to identify the called party or the calling party of the callback; the calling number will be re-changed in the Connect re-sent in the PPS service, so as to meet the number display requirement of the callback. Since the calling party of the callback is generally in an international roaming state, this change of the calling number to be displayed often cannot be well supported under the international roaming state.